1. Field of the Invention
The present invention relates generally to disk drives, and more particularly to a disk drive having a breather shroud.
2. Description of the Prior Art
The typical hard disk drive includes a head disk assembly (HDA) and a printed circuit board assembly (PCBA) attached to a disk drive base of the HDA. The head disk assembly includes at least one magnetic disk, a spindle motor for rotating the disk, and a head stack assembly (HSA) having an actuator assembly having at least one transducer head, typically several, for reading and writing data from the disk. The printed circuit board assembly includes a servo control system in the form of a disk controller for generating servo control signals. The head stack assembly is controllably positioned in response to the generated servo control signals from the disk controller. In so doing, the attached heads are moved relative to tracks disposed upon the disk.
A topic of concern is the desire to reduce the effects of airflow generated within the disk drive due to rotation of the disks. Of particular concern is the occurrence of airflow which may tend to excite a resonance response of the actuator assembly. This results in an increase in the percent off track values of the associated head. Further, such disk rotation induced airflow may result in a force applied to the actuator assembly, i.e., windage. Further, such disk rotation induced airflow may result in vibration of the disk or disk flutter. It is contemplated that the disk rotation induced airflow tends to become turbulent radially beyond the outer disk edges due to boundary layer separation occurring within various cavities within the disk drive. Such turbulent airflow further tends to impact the resonance response of the actuator assembly and disk flutter. Another topic of concern is the regulation of airflow between the internal and external environments of the disk drive. In this regard, it is desirable to filter airflow entering the disk drive for undesirable particulates and chemical compounds. Moreover, regulation of humidity within the disk drive is of concern. The foregoing functions of shrouding and filtering have been accomplished via various separate and discrete subcomponents which must be all manufactured and assembled into the disk drive. Such manufacture and assembly of the subcomponents into the disk drive increase the costs of disk drives. Accordingly, there is a need in the art for an improved disk drive for mitigation of such disk rotation induced airflow and for filtering airflow entering the disk drive at a lower cost in comparison to the prior art.
An aspect of the invention can be regarded as a disk drive which includes at least one rotatable disk including a disk edge and a disk drive housing having a breather hole formed through the disk drive housing. The disk drive further includes a breather shroud in mechanical communication with the disk drive housing. The breather shroud includes a shroud portion positioned adjacent the disk. The shroud portion is formed to extend along the disk edge for mitigating airflow adjacent the disk. The breather shroud further includes an air filter housing portion integrated with the shroud portion. The air filter housing portion is disposed adjacent the breather hole for filtering airflow through the breather hole. The air filter housing portion is positioned with the shroud portion between the air filter housing portion and the disk edge for mitigating airflow from the breather hole to adjacent to the disk.
According to an embodiment of the present invention, the air filter housing portion includes an elongate passageway having a passageway inlet extending to a passageway outlet. The passageway inlet is disposed in fluid communication with the breather hole. The shroud portion is disposed between the passageway outlet and the disk edge for mitigating airflow from the breather hole to adjacent to the disk. Further, the air filter housing portion includes a channel formed in the air filter housing portion. The passageway is formed between the channel and the disk drive housing. The air filter housing portion includes an inner cavity, and the passageway outlet extends to the inner cavity. The air filter housing portion includes a particulate filter extending across the inner cavity for filtering particulates from airflow through the breather hole. The air filter housing portion includes a chemical compound filter disposed within the inner cavity for removing chemical compounds from airflow through the breather hole. The chemical compound filter may be a chemical trap and an adsorbent. The disk drive housing includes a disk drive cover, and the breather hole is disposed through the disk drive cover. The breather shroud may be attached to the disk drive cover. The disk drive housing may further include a disk drive base, and the breather shroud may be disposed in compression between the disk drive cover and the disk drive base. Further, the breather shroud may be formed of an electrostatic dissipative material. The breather shroud may be formed of a conductive material.
According to another aspect of the present invention, there is provided a breather shroud for use in a disk drive as described above.